Abstract # 2397 Poster # 41:

Scheduled for Thursday, June 19, 2008 05:00 PM-07:00 PM: Session 4 (Ball Rooms A and B) Poster Presentation

Temperament and Daytime Sleep/Wake States in Neonatal Rhesus Macaques

D. B. Kay1, J. D. Higley2, M. Marsiske1 and S. J. Suomi3
1University of Florida, Clinical and Health Psychology, PO Box 100165, Gainesville, Florida 32610-0165, USA, 2Brigham Young University, Department of Psychology, 3Laboratory of Comparative Ethology, NICHD, NIH
     Infant sleep is an important developmental behavior influenced by a complex interplay between endogenous and exogenous factors. We investigated the relationship between paternity, birth weight, neonatal diurnal sleep and temperament. Nursery-reared rhesus macaques (Macaca mulatta; N=144) were kept under controlled conditions for 30 days post-birth. Sleep/wake states (1=sleep, 2=transition, 3=wake) were observed and recorded once per two hours daily (8am-8pm) and averaged over 30 days. ANCOVA was performed. Paternal grouping was the independent variable. Birth weight and four major factors of the Brazelton temperament test for monkeys (orientation, state control, motor maturity and activity) were covariates. The dependent variable was diurnal sleep. ANCOVA revealed a significant paternity effect [Roy’s largest root (17,121)=2.14, p<0.001]. Controlling for paternal group, greater state control [Roy’s largest root (1,121)=8.10, p<0.01] and lower birth weight [Roy’s largest root (1,121)=8.78, p<0.01] were significantly related to more diurnal sleep. Higher state control scores are associated with easier temperament and positive development; conversely, low birth weight reliably predicts negative developmental outcomes; both are linked to more diurnal sleep. One possible interpretation to this finding is that more diurnal sleep is related to neuronal development buffering against negative outcomes of low birth weight while facilitating/marking development in healthy infants. More research is needed to determine directionality between sleep and development/temperament.